two completely made up stories to illustrate a few things: Story #1 100 donors gave 250EUR each. We use 5000EUR of that for some early mech protos. Then we go "Hallo MURATA, we need 100 special custom-made connectors to plug that display flex cable in." MURATA answers "No way, sorry" We have to cancel the project due to this and we will pay back 250EUR<donated_amount>*((25000-5000)/25000) = 200EUR (minus handling fees) to our donors Story #2 1000 donors gave 100EUR each. We use 5000EUR of that for some early mech protos. Then we go "Hallo MURATA, we need THOUSAND special custom-made connectors to plug that display flex cable in." MURATA answers "Umm, OK. That's feasible" We DON'T have to cancel the project due to this and we will NOT have to pay back 100EUR<donated_amount>*((100000-5000)/100000) = 95EUR (minus handling fees) to our donors. However if we had to then obviously the "loss" for each donor is way smaller than in story one. To compare: for a 250EUR the refund would be 250*0.95=237.50 and thus the "loss" only 12.50EUR instead of 50EUR - that's the smaller individual risk. The answer from MURATA for 1000 items (vs. 100) represents the lower project risk.